bromeliad color isn't really determined by kelvin rating. It is more light intensity that determines that, and there are literally tons of different situations that can determine if you have enough light or way too much/not enough. First off, what type of bulb is this? i'm assuming fluorescent, but i could be wrong. If it is incandescent, its better off in the garbage. Light intensity can be measured in a couple different ways, most common being lumens. This can be a problem because lumens in based on how bright the human eye perceives it (mainly light in the green spectrum) and plants do not use green light. That is why they look green to us. The light simply bounces off them and is not absorbed. In general though, the lumen rating can tell us how useful the bulb will be to growing plants. A 26 watt spiral cfl usually puts out about ~1200 lumens depending on the brand. That would be enough for a small tank (maybe a ten gallon or so) The height of the bulb over the tank also plays a big role. Even a 150 watt metal halide could be not enough light for plants a ten gallon of not properly placed.
So we really cannot answer your question without more information. What type of bulb is it? what type of fixture? Does it have a reflector? What size tank are you lighting? What light level do you want to achieve (low light and slow growth, or high light with fast growth and vibrant colors). As you can see, vivarium lighting can be a hassle to get right haha